It is well known to utilize an elastomer seal in a hydraulic piston and cylinder assembly such as shown in the safety valve in U.S. Pat. No. 4,161,219.
However, elastomer seals are limited as to the temperatures in which they can operate, the pressures which they can withstand, and the length of time before they must be replaced.
The present invention is directed to a metal-to-metal dynamic seal which can be used in various applications having a double acting piston and cylinder in extreme high pressure and temperature applications which surpass the limits of general elastomers. Furthermore, the present seal is directed to reducing the differential pressures across the seal when the piston is actuated. And in particular, the seal of the present invention is particularly useful in actuating a well safety valve which is subjected to high downhole pressures and temperatures.